Studies of voluntary movement focused on the role of the cerebellum. One issue was the contribution of the cerebellum to coordination. The results seem to indicate that the cerebellum is critical for the coordination of multijoint movement. One role of the cerebellum appears to be in the control of force. A second issue is the role of the cerebellum in motor learning. In tasks of motor learning, it has been demonstrated with additional studies that patients with cerebellar disturbances have difficulty with adaptation learning. A third issue is the role of the cerebellum in kinesthesia, the sense of movement. Results show a deficit in appreciation of velocity and duration in patients with cerebellar deficits. Using O~15 labelled water as a marker for cerebral blood flow in positron emission tomography ( PET) studies, we have been working on methods for improved anatomic correlation of regions of metabolic change by superimposing the PET image onto an MRI image. In studies of PET and functional MRI, we have shown plasticity of the motor cortex with transient deafferentation of a limb with an ischemic block. Studies of movement~related cortical potentials have focused on identifying dipoles for the generation of the different components and the development of techniques for measuring event~related desynchronization and coherence analysis of the EEG. The dipoles have been compared with areas of activation with PET and an excellent correlation has been found. Studies have been completed in patients with dystonia that show reduction in amplitude of some EEG components. Studies in the Biomechanics Laboratory of the Department of Rehabilitation Medicine have focused on the control of balance and gait. A study is in progress of gait in patients with cerebellar disorders . Other studies are being done of balance in patients with cerebellar deficits. Studies are ongoing recording muscle spindle activity during voluntary movement and passive stretch. A therapeutic trial of buspirone in cerebellar patients showed some improvement in those mildly affected.